December: Geminids
The constellation, which the meteor shower has been named after, is considered the radiant point of the shower, explains Ladia. In simple terms, as the Earth nears this debris, that constellation is the point from where the shower appears to begin, to us.
Ladia calls this radiant point a meteor shower’s “address in the sky”. Whichever constellation it seems to be coming from, he says, is what the meteor shower is named after: Lyrids for Lyra, Geminids for Gemini, Perseid for Perseus and so on.
How powerful a meteor shower is, depends on a number of factors, such as how numerous the debris is, the size of each individual particle, its luminosity, and its rate per hour. The standard for measuring that last factor, says Ladia, “is zhr or zenithal hourly rate: how many meteors can one person see per hour on a clear night. It is the measure of the quality of a meteor shower.”